Solid-state image sensors configured to receive light from an object with an image sensor such as a charge coupled device (CCD) and a complementary metal oxide semiconductor (CMOS) imager, output a signal for each pixel resulting from photoelectric conversion to obtain an image are known. To obtain a color image by using such a solid-state image sensor, color filters of R (red), G (green) and B (blue) are commonly provided for respective pixels over a light receiving surface of an image sensor to output signals of R, G, and B.
In the meantime, a structure in which a microlens array is arranged above pixels, multiple pixels are arranged below microlenses to further focus an image from a main lens on the pixels by using the microlens array is proposed as a structure of an imaging optical system. With this structure, a group of images having disparities in units of pixel blocks can be obtained, and the disparities allow a refocusing process or the like on the basis of distance estimation or distance information of an object. The optical configuration to further focus an image from the main lens by using the microlens array is referred to as a refocusing optical system.
One example of factors that degrade the quality of images captured by an image sensor is crosstalk referring to light incident on a pixel enters an adjacent pixel. For example, consider color filters for respective pixels in the Bayer array in which a row of G, B, G, B, . . . and a row of R, G, R, G, . . . are alternately repeated that are used in a common image sensor. If crosstalk is caused in the Bayer arrangement, color mixture leading to erroneous detection of light of different color components in the pixels may be caused and the color reproducibility of a captured image is degraded.
In the refocusing optical system described above, light beams from the main lens pass through the respective microlenses and are received by the light receiving surface of the image sensor at incident angles depending on the positions of the microlenses. Thus, crosstalk between pixels as described above may also be caused in the refocusing optical system.